1. Field of the Invention
The present invention relates generally to a method and apparatus for playing back videos, and more particularly, to a method and apparatus for providing additional information contained in videos.
2. Description of the Related Art
In general, Moving Picture Expert Group-4 (MPEG-4) refers to a digital bit stream protocol that can encode such contents as audio, video, and objects, and indicates a protocol capable of digitally representing and delivering a variety of multimedia contents. Since MPEG-4 is an object-based representation system, scene description information is needed to compose scenes. Such description information is called Binary Format for Scenes (BIFS). BIFS composes scenes by composing and mixing objects, moves MPEG-4 objects by describing interfaces with objects, and enables providing content for objects corresponding to a user's input among BIFS nodes.
FIG. 1 illustrates a structure of a conventional broadcast terminal. Referring to FIG. 1, the broadcast terminal includes a demultiplexer (DEMUX) 200, a video decoder 210, an audio decoder 220, a data decoder 230, a display 240 and a speaker 250.
The demultiplexer 200 separates video, audio, and data information individually from an MPEG Transport Stream (TS) received from the outside, and provides the separated information to the video decoder 210, the audio decoder 220, and the data decoder 230, respectively.
The video decoder 210 decodes the encoded video information, the audio decoder 220 decodes the encoded audio information, and the data decoder 230 decodes the encoded data information.
The display 240 converts the video information decoded by the video decoder 210 into a visible light signal and provides it to a user. The speaker 250 converts the audio information decoded by the audio decoder 220 into an audible signal and offers it to the user. When the video and/or audio information is composed based on objects, the display 240 and the speaker 250 may further exhibit information about the composition. In particular, the display 240 may further include an input interface (e.g., a touch screen module) through which objects included in video can be selected, and may receive specific selected objects contained in video or audio information through the input interface. If a specific object is selected by the user through the input interface, data corresponding to the selected object can be provided to the user through the display 240 and/or the speaker 250.
FIG. 2 illustrates an operation of a conventional broadcast terminal. Referring to FIG. 2, the broadcast terminal receives an MPEG TS in step 310, and then separates video, audio and data information individually from the received MPEG TS and decodes the separated information separately in step 320.
The decoded video and audio information is provided to the user through the display 240 and the speaker 250 in step 330. Here, the display 240 outputs the video information, which includes information indicating that the video or audio information is composed based on objects.
If an interaction with the broadcast terminal occurs from the user in step 340, the display 240 or the speaker 250 receives data information corresponding thereto from the data decoder 230 and then provides the data information to the user in step 350. However, if no such interaction occurs with a user, the operation proceeds to step 360, where the operation is completed.
Steps 310 to 350 stated above are repeated until a broadcast function of the broadcast terminal is completed.
Such BIFS-based broadcast service is generally provided to portable terminals capable of supporting Internet Protocol Television (IPTV) or Digital Multimedia Broadcast (DMB) service. With the portable terminal, the user may select menus and click buttons while enjoying content, and thus directly issue commands or control the portable terminal.
Meanwhile, a large-scale display device intended for a plurality of users, such as IPTV or large-sized advertising display board, does not include a separate input interface (e.g., a touch screen module) through which the user can directly select objects contained in video or audio information, and its operation is generally controlled using a remote control device (e.g. a remote controller). Therefore, the large-scale display device is designed to create a separate menu for selecting objects, provide a list of data information corresponding to the objects, and receive specific objects selected by the user. Thus, with use of the remote control device, the user checks a list displayed on a screen of the display device by selecting a menu for object selection, and reads data information by selecting a specific object from the list. In this case, the user must inconveniently select a plurality of menus to select a desired specific menu, and the interim menus displayed on the screen of the display device may damage the video.